[ELF] Enforce double-dash form for --color-diagnostics/--rsp-quoting/--symbol-ordering-file

They are LLD-specific and by convention we enforce the double-dash form to avoid
collision with short options (e.g. weird `-c olor-diagnostics` interpretation in
GNU ld). They are rarely used and to the best of my investigation the undesired
single-dash forms are not used in the wild.